如何在real-time-db FIREBASE中检查数据

Question

我想检查/比较一下这个数据中是否有值：

例：

const uid = '35nv594aotgcv'

#check if uid is inside

firebase
 .database()
   .ref('followers/2mvouwB0E0aEN5MnAhOLWaHiu6b2')
     .once("value", snapshot => {
         if (snapshot.exists()) {
            const data = snapshot.val(); // data are the other two uid's in the image above
         }
     });

那么如何检查const uid = '35nv594aotgcv'是否在快照数据中？

或者如果我有一个带有uid的数组，例如const uids = ['234', '343', '3242', ...]

Answer 1

如果我理解正确，您正在寻找DataSnapshot.hasChild() 。 通过它，您可以检查快照是否具有某个子节点。

就像是：

firebase
 .database()
 .ref('followers/2mvouwB0E0aEN5MnAhOLWaHiu6b2')
 .once("value", snapshot => {
   if (snapshot.hasChild('35nv594aotgcv')) {
     console.log('Yes');
   }
 });